Swimming pools
A swimming pool is a tank that works the other way round: water pushes from the inside, permanently, and is chemically aggressive. No other structure puts waterproofing under such continuous strain.
- Flexible system, tested for permanent immersion in chlorinated water
- Every critical point — corners, fittings, joints — has its dedicated component
- Verifiable with a watertightness test before the finish is laid
- 1
Substrate preparation
The pool's concrete must be sound, clean, with fillets already formed at the corners between walls and floor.
On absorbent or poorly cohesive substrates, consolidate first with AQUAFIN-Primer. Imperfections are levelled with ASOCRET-M30.
- 2
Flexible waterproofing
A flexible two-component cementitious slurry is applied in two crossed coats, with the minimum dry thickness required by class CM O1 P under EN 14891: AQUAFIN-2K/M-PLUS for the standard cycle, AQUAFIN-RS300 where faster recoating times are needed. On pool surrounds and showers (class W3-I), single-component AQUAFIN-1K-PREMIUM can also be used.
The sealing tapes and pre-formed corners of the ASO/ADF System are embedded in the first coat at all corners, construction joints and expansion joints.
- 3
Critical points and accessories
Skimmers, inlet and return fittings, main drain, underwater lights and service penetrations are treated with the dedicated sleeves of the ASO/ADF System — never left to the slurry spread over the surface alone. Movement joints inside the pool require a sealant suitable for permanent immersion; on the floors around the pool, expansion joints are sealed with PRO FLEX.
A system is judged by the completeness of these accessories, not by the product spread over the flat surface.
- 4
Laying tiles or mosaic
The finish is laid with adhesive and grout specifically suitable for permanent immersion, once the underlying waterproofing has fully cured.
- 5
A second line of defence, on large pools
On large pools, sports pools and thermal facilities it is worth making the pool's concrete waterproof too, with the crystalline admixture BETOCRETE-CP350-CI dosed at the batching plant and waterstops on construction joints.
For thermal pools, compatibility with the specific water composition must always be checked, as it is often more aggressive than simple chlorination.
- 6
Watertightness test and filling
The watertightness test is carried out once the waterproof coating is complete and before the finish is laid: the pool is filled and the drop in level is measured over time, net of evaporation.
The first permanent filling must be gradual, respecting the curing times of adhesives and grouts, so as not to stress the structure.
Pool build-up and critical points
Products for this system
Selected from the Probar 2026 catalogue for this application.
AQUAFIN-2K/M-PLUSFlexible two-component cementitious waterproofing slurryWaterproof slurries and mortarsArt. 204600Schomburg
AQUAFIN-RS300Fast reactive hybrid waterproofingFast liquid membranesArt. 204208Schomburg
AQUAFIN-1K-PREMIUMSingle-component flexible cementitious waterproofing slurryWaterproof slurries and mortarsArt. 204609Schomburg
AQUAFIN-PrimerReady-to-use safety primer for preparing cementitious substratesWaterproof slurries and mortarsArt. 203901Schomburg
Sistema ASO / ADFSealing tapes, corners and sleevesSealants and tapes—Schomburg
ASOCRET-M30Waterproof multi-purpose mortar up to 30 mm — 4 in 1Concrete repairArt. 205539Schomburg
BETOCRETE-CP350-CIPowder waterproofing admixture with crystalline technology and anti-corrosion actionConcrete admixturesArt. 206456Schomburg
PRO FLEXHigh-modulus elastic polyurethane sealantSealants and tapesPRF-300 / PRF-600Frequently asked questions
What waterproofing product is used for a swimming pool?
A flexible two-component cementitious slurry with declared resistance to chlorinated water and crack-bridging capability, classified under EN 14891 and suitable for permanent immersion. Rigid products are not suitable because the tank moves with the filling cycles.
Can an existing pool be waterproofed without removing the coating?
Only if the tiles are perfectly bonded and the substrate underneath is sound. In most renovations it is better to remove the coating: leaks almost always come from the junctions and penetrations, which have to be exposed anyway.
Is the crystalline admixture needed if the inside is going to be coated anyway?
It is not mandatory, but on large, sports or thermal pools it gives a second barrier independent of the coating. On a facility that cannot go out of service, it is a matter of continuity, not redundancy.
How well does it resist thermal water?
It depends on the specific chemical composition, which must be analysed: some thermal waters are far more aggressive than chlorinated water and call for resin-based rather than cementitious coatings.
Continue reading
White tank
The concrete structure is itself the waterproofing. No membrane to lay, no sheet to protec…
Retaining wall in groundwater
When a below-grade structure sits in groundwater, hydrostatic pressure is permanent and ac…
Leaking basement
The room is built, the backfill is done, and water gets in. The work is carried out from t…
Reinforced concrete repair
Spalling cover concrete is not a cosmetic issue: it is the visible symptom of a process ea…